Voltage-controlled oscillator

About: Voltage-controlled oscillator is a research topic. Over the lifetime, 23896 publications have been published within this topic receiving 231875 citations. The topic is also known as: VCO.

A double-band high-power microwave source

Abstract: In order to increase the power conversion efficiency of a magnetically insulated line oscillator (MILO), an axially extracted virtual cathode oscillator (VCO) is introduced to utilize the load current in the MILO, so it is called the MILO-VCO. In this device, the MILO and VCO are operated synchronously and generate high-power microwaves. The MILO-VCO is investigated in detail with particle-in-cell (PIC) methods (KARAT code). In simulation, the diode voltage is 640 kV and the current is 50 kA. The total peak power of the MILO-VCO is 5.22 GW and the corresponding power conversion efficiency is 16.3%. In the MILO-VCO, the peak power of the MILO is 3.91 GW and its frequency is 1.76 GHz; the peak power of the VCO is 1.33 GW and its frequency is 3.79 GHz.

Balanced colpitt oscillator MMICs designed for ultra-low phase noise

Abstract: Balanced voltage-controlled oscillator (VCO) monolithic microwave integrated circuits (MMICs) based on a coupled Colpitt topology with a fully integrated tank are presented utilizing SiGe heterojunction bipolar transistor (HBT) and InGaP/GaAs HBT technologies. Minimum phase noise is obtained for all designs by optimization of the tank circuit including the varactor, maximizing the tank amplitude, and designing the VCO for Class C operation. Fundamental and second harmonic VCOs are evaluated. A minimum phase noise of less than -112 dBc at an output power of 5.5 dBm is achieved at 100-kHz carrier offset and 6.4-GHz oscillation frequency for the fundamental InGaP/GaAs HBT VCO. The second harmonic VCO achieves a minimum measured phase noise of -120 dBc at 100 kHz at 13 GHz. To our best knowledge, this is the lowest reported phase noise to date for a varactor-based VCO with a fully integrated tank. The fundamental frequency SiGe HBT oscillator achieves a phase noise of -108 dBc at 100 kHz at 5 GHz. All MMICs are fabricated in commercial foundry MMIC processes.

Analysis, simulation, and applications of passive devices on conductive substrates

Abstract: The wireless communication revolution has spawned a revival of interest in the design and optimization of radio transceivers. Passive elements such as inductors, capacitors, and transformers have the potential to improve the performance of key RF building blocks. Their use, though, not only necessitates proper modeling of electrostatic and magnetostatic effects, but also electromagnetic parasitic substrate coupling. This work focuses on the analysis and application of such passive devices. From Maxwell's equations, an accurate and efficient technique is developed to model the device over a wide frequency range. In particular, we demonstrate techniques for calculating the loss when such devices are fabricated in the vicinity of conductive substrates such as silicon. Energy couples to a conductive substrate through several mechanisms, such as through electrically induced displacement and conductive currents, and by magnetically induced eddy currents. Green functions for Poisson's equation and the eddy current partial differential equations are derived and employed to account for the various loss mechanisms. Numerical techniques are developed to efficiently and accurately compute the underlying Green functions. These techniques have been compiled in a user-friendly software tool, ASITIC, “Analysis and Simulation of Inductors and Transformers for Integrated Circuits”. This tool allows circuit and process engineers to design and optimize the geometry of passive devices and the process parameters to meet electrical specifications. Two key RF building block applications, a 4.4 GHz voltage controlled oscillator (VCO) and a distributed amplifier, are presented. In the VCO, the center-tapped monolithic inductor is at the heart of the resonant tank, a key component in determining the phase noise and power dissipation in the VCO. In the distributed amplifier, lumped inductors and capacitors, or on-chip transmission lines, allow broadband operation. The losses in the passive devices determine the achievable gain and power dissipation. Optimization of such passive devices is thus integral in the design of such building blocks.

A Low Voltage and Power $LC$ VCO Implemented With Dynamic Threshold Voltage MOSFETS

Abstract: A 1.1-GHz voltage control oscillator (VCO) using a standard 0.18-mum CMOS 1P6M process is fabricated. The VCO was designed with dynamic threshold voltage metal-oxide-semiconductor field-effect transistors and extremely-low-voltage and low power operation is achieved using on-chip transformers in positive feedback loops to swing the output signals above the supply and below the ground potential. This dual-swing capability maximizes the carrier power and achieves low-voltage performance. This VCO prototype is designed for a 0.34-V supply voltage while the output phase noise is -121.2dBc/Hz at 1-MHz offset frequency at the carrier frequency of 1.14GHz, the figure of merit is -192.0dB. The total power consumption is 103.7muW with the 0.34-V supply voltage. Tuning range is from 1.06 to 1.14GHz about 80MHz while the control voltage was tuned from 0 to 1.8V. The die area is 0.625times0.79mm2

A 40 Gs/s Time Interleaved ADC Using SiGe BiCMOS Technology

Abstract: The search for high speed, high bandwidth A/D converters is ongoing, and techniques to push the envelope are constantly being developed. In this paper an open loop, scalable, time-interleaved ADC architecture is presented, as well as a 60 GHz Colpitts oscillator. With the use of double-sampling, the timing skew requirements between channels is greatly relaxed, allowing sampling rates of up to 40 Gs/s at 4-bits of accuracy. This circuit is implemented using the IBM 8HP SiGe technology, with fT of 210 GHz. The performance of the 8HP ADC is validated by measurement. In addition, simulations with an experimental 8XP transistor model provided by IBM with a 350 GHz fT suggest that 30% more circuit speed is possible by just swapping the transistors.